Asphalt agricultural mulch



United States Patent The present invention is concerned withestablishing and sustaining and promoting plant growth utilizingasphaltic emulsions. In accordance with the present invention, anasphaltic emulsion containing an acid such as gibberellic acid is usedin a manner to substantially enhance and maintain agricultural growth.

It is well known in the art to use various agricultural growthpromoters, particularly in aqueous solutions. It has also been suggestedin the art to use various asphaltic emulsions for the purpose ofcontrolling and improving the moisture content of the seed area. Inaccordance with the present invention, not only is the moisture contentof the seed area controlled, but also the agricultural growth materiallyimproved.

Millions of acres of potentially valuable grazing lands in the westernhalf of the United States, along with areas even more vast in othercountries, normally do not receive sufiicient rainfall to reseed andestablish grass crops suitable to maintain livestock within economicallyfeasible geographical limits. Imprudent management in marginal croppingareas and overgrazing of poorly established grasslands followed by winderosion has only served to accentuate the problem. Attempts to seed orreseed these semi-arid lands with suitable range grasses have resultedin the expediture of large sums in labor and material. Even so, theseeding techniques employed in the past have been only about 10 tosuccessful in the moisture limited areas.

It has now been discovered that the moisture necessary for both seedgermination and early plant growth can be maintained in the seed bed byapplying certain asphalt emulsions over such seed beds according to themethods hereinafter set forth in detail.

Asphalt emulsions which are suitable for use with this invention may beeither acidic (cationic) or basic (anionic) although the acidicemulsions are preferred. Both are asphalt-in-water emulsions. Typicalspecifications for both types are listed in the following table.

TABLE I Characteristics and composition of acidic and basic emulsionsSoftening Point, F Composition, Wt. percent:

Water Asphalt Emulsifier (Preferably polyamines for acidic emulsions,fatty acids for basic):

NaOH HCl (36%) Suitable emulsifying agents for use in preparing theseemulsions include the following:

CATIONIC AGENTS 1) Primary, secondary, tertiary, and polyamine saltssuch as the diamine dichloride,

3,210,173 Patented Oct. 5, 1965 "Ice where R is an alkyl chain with 1618carbon atoms. In general, the alkyl chains of the amines may contain8-22 carbon atoms with 1618 being preferred.

(2) Amines such as those used in forming the salts of (1) condensed with1-10 moles of ethylene oxide per mole of amine such as where R is asdefined in (1).

(3) Quaternary ammonium salts such such as [R -N]+Cl- (4) Dimethylatedamine salts such as R-Nflll- (5 Aromatic amine salts and cyclic aminesalts. (6) Z-imadazoline.

ANIONIC AGENTS Alkali metal salts of fatty acids such as o R- ('3ONa+where R is an alkyl chain with 8-22 carbon atoms, preferably 14-18. Thepotassium salt may also be used. Also, the emulsifying agent is notalways one specific compound but could be a mixture of salts of fattyacids in which R varied in length. Examples of these are a sodium saltof pine wood ligin and a salt of a long chain acid resin from thedestructive distillation of pine wood stumps; also fine clays such asbentonite can be used.

Whereas, the actual emulsifying agents for the cationic and anionicemulsions are the amine salts or fatty acid salts, these salts areusually formed in the aqueous emulsifying solution by reaction of theamine with an acid such as HCl and the fatty acid with a base such asNaOH. Possible substitutes for the HCl and NaOH therefore exist. Aceticacid (CH COOH) or nitric acid (HNO could be used instead of HCl on amole per mole basis. Also, KOH could be used instead of NaOH althoughthe latter is cheaper.

Other petroleum products may be used in lieu of asphalt in theseemulsions or as non-emulsified liquids providing they are of a suitableviscosity for application by spraying, form a continuous film which ispenetrable to young seedlings but essentially impenetrable to water, anddo not possess a high degree of herbicidal properties. Suitablepetroleum products for this use include crude oils low in sulfurcontent, petroleum waxes, wax and asphalt mixes, and residua.

For the purposes of this invention, the emulsions set forth in Table Imay, for Want of a better term, be referred to as emulsion concentrates.For the purposes of this invention, such emulsions are further dilutedwith water as for example with 0.4 to 3 parts of water prior toapplication. For minimizing evaporation losses with soils in general, ithas been found that optimum results are obtained when about 1.0 to 1.70,preferably about 1.3, volumes of water are employed per equivalentvolume of emulsion concentrate. More specifically, maximum effectivenessin retarding evaporation from a silt loam type soil while using aminimum amount of emulsion is obtained by spraying onto the soil anemulsion as char- 3 acterized in Table I diluted to the extend of1.18:0.25 to 1.47:0.25 volumes of water per volume of emulsion, suchdilution increasing linearly from the low dilution to the higherdilution as the soil density decreases from 4 Society 81, 24241959).Gibberellic derivatives such as mineral ion salts may also be used.These mineral ion salts may comprise ammonium, Co, Rd, Cu, Mn, Pb, andsodium. In addition, the actyl, diacetyl, butyrl, benzoyl about 1.60 to1.20 gm./cm. These emulsions may be 5 derivatives of gibberellic acidare also effective. prepared in the conventional manner as follows. Inorder to further illustrate the invention, a number The emulsifyingsolution of the desired formulation of experiments were carried oututilizing as a crop Caliat a temperature of 120 to 150 F. and theasphalt at fornia Wonder Sweet Peppers. The amount of asphalt atemperature of about 240 F. may be fed in separate in the emulsion wasbout wt. percent and the amount streams to a conventional colloid mill.Other conven- 10 of gibberellic acid present was about 2.66 gms./gal.The tional techniques for effecting emulsification may be emamount ofemulsion utilized was about 300 to 400 ployed if colloid milling is notconvenient. The preferred gals/acre. The results of these tests areillustrated-in emulsification temperature is about 180-190 F. a thin thefollowing data.

TABLE 1 Average Ht. Inches Av. Increase Group After 10 Range in GrowthOver 10 Days, in Height, in Over 10 Days Period Days Period 1. AsphaltieMulch with Gibberellic Treat, 73 rug/plant 9. 9 7-13 0. 71 .5. 0 2.Asphalt Mulch 6.4 4-13 0.33 2.3 3. N0 Mulch 6.7 31-13% .30 3.0

TABLE 2 Individual plant heights 10 days after test as compared to theiroriginal heights it Group Less Greater Greater than Double than Triplethan Double Double Triple 1. Gibb. Acid, 73 lng.!plant in Asphalt Mulch1 1 3 2 2. Asphalt Mulch"... 5 1 1 a. N0 Mulch 5 3 2 I TABLE 3 InchesAverage Average Ht. Range in Growth] Increase Group After 12 DaysHeight, in. Plant Over 12 Over 12 Days Days Period Period 1. 73 mg.Gibb. Acid in Asphalt l0. 9 7 4-15 86 6. 0 2. Asphalt 6.6 5 /2-13% .362. 5 3 No Mulch 7.2 3-15 .35 as continuous film of such emulsions willretard evaporation rates by 90 to 99% as compared to bare soil. SuchTABLE 4 emulsions (based on undiluted emulsion concentrate) should beapplied at a rate in the range of 150 to 1000, Individual Plan! eightslz alays after tests as preferably 300 to 750 ga. per acre of coverage.compared to Orlgmal helgius Thus, in accordance with the presentinvention, gibberellic acid (Eastman Distillation Products No. 7444-85%) is used in an emulsion such as described above, Group Doible ffig fTrifle figf particularly in an acidic type emulsion. It IS preferredDQ111318 Double Triple that the amount of asphalt in the mulch rangefrom about 25 to by weight as compared to the water 60 g g' 3 3% 1present, preferably from about 40 to 55% by weight as 2. as haltaufjl: 6compared to the water present. No Mulch 4 The amount of gibberellic acidmay vary appreciably as, for example, in the range from about 0.00004gms./ gal. to 2.66 gms./gal., preferably in the range from about TABLE 5.0004 gms /gal. to .0008 gms./gal. When utilizingasolu- Individual plantheights after 13 days on test tlon of this sort, the amount applied peracre is in the range from 100 gals. to 1000 gals, preferably in therange Less Greater Greater from about 325 to 600 gals./ acre. Group gDouble than Triple a The gibberellins are part of a group of naturalgrowth on 6 Double Triple regulating hormone systems in higher plants(F. H. 1 Stodola, Source Book on Gibberellin 18281957, Agric. 1 ResearchService, US. Dept. Agric., Peoria, 111. 1958 3 and C. A. West, B, O,Phinney, Jr., American Chem.

TABLE 6 Thus, after a 13 days test period, the results indicate that theGibberellic Acid California Wonder Sweet Pepper G igrerageits. GlnchelslI Average Plants (containing an asphalt mulch) had an average figg jgRange igg gfi fgggi; higher growth rate of 228% when compared with plainl3DayPer10d Perlod 5 asphalt mulch and 253% greater than pepper plantsthat were not mulched. &3 2:12 3 3': Additional tests were conductedutilizing as the crop. 7.3 3-15 .36 3.6 Wonder Pepper Plants. Theresults of these tests are shown in the following tables.

TABLE 7 Gibberellic acid experiment on California Wonder Pepper Plants73 mg. Gibb. Aeid/plant/IOO m1. of emulsion 100 ml. Asphalt Mulch/PlantPlant No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Days Height in Inches TABLE 8Gibberellic acid experiment on California Wonder Pepper Plants [NoMulch] Plant No 15 16 17 18 19 20 21 22 23 24 Days Height in Inches 1All plants received a feeding of gms. of Cottonseed meal (contains 41%protein or 7% nitroge 2 ml. distilled water/plant. 3 Put on aqueousGibb. Acid Test (73 mgJplant in 100 ml. distilled water).

The results of the foregoing may be summarized in the following tables.

TABLE 9 Average growth in inches/plant/day over the following periods 1Half oi the number of plants were put on Aqueous Gibb. Acid.

TABLE Ratio of the average inches of height gained in plant groups fromTable 1 10 Day 18 Day 24 Day 29 Day 31 Day Period Period Period PeriodPeriod Gibb. Acid in Asphaltic Mulch:

Asph. Mulch 2. 33:1 2. 00:1 1. 68:1 1. 51:1 1. 50:1 Gi b. Acid inAsphaltic MulchzNot Mulched 1. 93: 1 1. 77:1. 1. 50:1 NotMulehed=Asphaltic Mulch 1. 21:1 1.13:1 1. 12:1

1 Half of the number of plants Wereput on Aqueous Gibb. Acid.

TABLE 11 15 amount of asphalt present as compared to the water isAverage growth in inches/plant/day over the following periods Ratio 01the average inches of height gained in plant groups from Table 1 10 Day17 Day 23 Day Period Period Period Aqueous Gibb. Acid:No Gibb.Acid.-- 1. 49:1 1. 39:1 1. 56:1

Thus, the present invention is concerned with the use of an acid,particularly gibberellic acid in conjunction with an asphalt emulsionwherein the aqueous phase is the continuous phase.

What is claimed is:

'1. Improved asphalt composition for mulching seeded areas whichcomprises an asphalt-in-Water emulsion containing a gibberellin selectedfrom the class consisting of gibberellic acid, the mineral salts ofgibberellic acid and the organic esters of gibberellic acid wherein theamount of gibberellin present is in the range from about 0.00004 gms./gal. to about 2.66 gms./ gal.

2. Composition as defined by claim 1 wherein the amount of asphaltpresent in said emulsion is in the range from about 25 to 60% by weightas compared to the water.

3. Composition as defined by claim 2 wherein the about 40 to by weight.

4. Composition as defined by claim 3 wherein said asphalt is an acidicasphalt.

5. Composition as defined by claim 1 wherein said gibberellin isgibberellic acid and the amount of gibberellic acid present is in therange from about .0004 gms./ gal. to .0008 gms./gal.

6. Improved process for mulching a seeded area which comprises coatingsaid seed bed with an asphalt-in-water emulsion containing a gibberellinselected from the class consisting of gibberellic acid, the mineralsalts of gibberellic acid and the organic esters of gibberellic acidwherein the amount of gibberellin present is in the range from about000004 gmsjgal. to about 2.66 gms./gal.

References Cited by the Examiner UNITED STATES PATENTS 1,882,377 10/32Whittelsey 71.22.1 X 1,988,175 l/ 35 Merrill 47-9 X 2,333,959 11/45Smith 479 2,741,550 4/56 Edmond et a1. 71-2.4 2,829,040 4/58 Darin eta1. 712.5 2,842,051 7/58 Brian et a1. 712.5 2,851,824 9/58 Campbell 711X 2,936,226 5/60 Kaufman et al 711 2,974,030 3/61 Geary.

2,995,433 8/61 Goren et a1. 71-25 3,061,974 11/62 Louis et al 479 OTHERREFERENCES Smith (II): The Effect of Asphalt Mulches on TheStabilization of Soils and Aggregate Materials and on VegetationalCover, an abstract of a thesis, 1953, 11 pages.

LEWIS GOTTS, Primary Examiner.

MAURICE A. BRINDISI, Examiner.

1. IMPROVED ASPHALT COMPOSITION FOR MULCHING SEEDED AREAS WHICHCOMPRISES AN ASPHALT-IN-WATER EMULSION CONTAINING A GIBBERELLIN SELECTEDFROM THE CLASS CONSISTING OF GIBBERELLIC ACID, THE MINERAL SALTS OFGIBBERELLIC ACID AND THE ORGANIC ESTERS OF GIBBERELLIC ACID WHEREIN THEAMOUNT OF GIBBERELLIN PRESENT IN THE RANGE FROM ABOUT 0.00004 GMS./GAL.TO ABOUT 2.66 GMS./GAL.